// This file is part of Substrate.

// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

//! Network event types. These are not the part of the protocol, but rather
//! events that happen on the network like DHT get/put results received.

use bytes::Bytes;
use libp2p::core::PeerId;
use libp2p::kad::record::Key;
use std::borrow::Cow;

/// Events generated by DHT as a response to get_value and put_value requests.
#[derive(Debug, Clone)]
#[must_use]
pub enum DhtEvent {
    /// The value was found.
    ValueFound(Vec<(Key, Vec<u8>)>),

    /// The requested record has not been found in the DHT.
    ValueNotFound(Key),

    /// The record has been successfully inserted into the DHT.
    ValuePut(Key),

    /// An error has occurred while putting a record into the DHT.
    ValuePutFailed(Key),
}

/// Type for events generated by networking layer.
#[derive(Debug, Clone)]
#[must_use]
pub enum Event {
    /// Event generated by a DHT.
    Dht(DhtEvent),
    /// Opened a substream with the given node with the given notifications protocol.
    /// The protocol is always one of the notification protocols that have been registered.
    NotificationStreamOpened {
        /// Node we opened the substream with.
        remote: PeerId,
        /// The concerned protocol. Each protocol uses a different substream.
        protocol: Cow<'static, str>,
        generic_data: Vec<u8>,
        notif_protocols: Vec<Cow<'static, str>>,
        rpc_protocols: Vec<Cow<'static, str>>,
        version_string: Option<String>,
    },

    /// Closed a substream with the given node. Always matches a corresponding previous
    /// `NotificationStreamOpened` message.
    NotificationStreamClosed {
        /// Node we closed the substream with.
        remote: PeerId,
        /// The concerned protocol. Each protocol uses a different substream.
        protocol: Cow<'static, str>,
    },

    /// Received one or more messages from the given node using the given protocol.
    NotificationsReceived {
        /// Node we received the message from.
        remote: PeerId,
        /// Concerned protocol and associated message.
        messages: Vec<(Cow<'static, str>, Bytes)>,
    },
}

/// Role that the peer sent to us during the handshake, with the addition of what our local node
/// knows about that peer.
///
/// > **Note**: This enum is different from the `Role` enum. The `Role` enum indicates what a
/// > node says about itself, while `ObservedRole` is a `Role` merged with the
/// > information known locally about that node.
#[derive(Debug, Clone)]
pub enum ObservedRole {
    /// Full node.
    Full,
    /// Light node.
    Light,
    /// Third-party authority.
    Authority,
}

impl ObservedRole {
    /// Returns `true` for `ObservedRole::Light`.
    pub fn is_light(&self) -> bool {
        matches!(self, Self::Light)
    }
}
